A rare and expensive drug found in Cambridge, Massachusetts, distributed by the being known only as Dr. PrepStone aka the Pterodactyl. It is basically ground up cow utter which, when smoked, releases all of the cow's hormones in addition to its remaining milk. It can cause anything from hallucination to seizures.
It was originally discovered by British Prime Minister Winston Churchill, who created it in an experiment alongside Bono's grandfather, Bono. Its full potential was not known until along came a Vietnamese doctor named Timbuk the Second, commonly written as Timbuk II. Warning: can cause induced menstrual cycle in male users.

I just smoked an entire bag of moo with my buddy and his belly button started bleeding. Then he vomited up his small intestine!

A female breeder. Short for Moomy, like "Mom" is short for "Mommy." So-called because such women drop offspring like cows do, seeming to have little other purpose in life, and sometimes conspicuously breastfeed them in public. They often also bovinely ignore them...unless you attempt to discourage their crotchfruit from screaming or otherwise misbehaving in public, in which case they will begin lowing like an angry cow whose calf has been threatened.

That stupid Moo was letting her little bastard tear up the entire supermarket while she stood obliviously in the frozen foods aisle.

A negative word for any woman, esp. a soccer mom, who thinks that children in general (not just her own, but every child on the planet) are the only important things in life and everything else (friends, lovers, dreams, etc.) are nothing.

Mrs. Andrews is such a moo. She is completely obsessed with children and, wuite frankly, lacks dreams for herself.

A mildly offensive term of abuse normally directed at the wife. Used in conjunction with words like daft, stupid, silly etc. Popularised by the Alf Garnet characture in the sitcom 'Til Death Do Us Part'